<?php 
	//define constant
	define('_pi', 3.14);
	echo _pi."<br>";

	$radius = 4;

	$diameter = $radius * 4;
	$circumference = _pi * $diameter;
	$area = M_PI * pow($radius, 2);

	echo "This circle has ...<br>";
	echo "A radius of ".$radius."<br>";
	echo "A diameter of ".$diameter."<br>";
	echo "A circumference of ".$circumference."<br>";
	echo "An area of ".$diameter."<br>";
?>
